Changes in tillage practices, fewer acres in crops, adoption of conservation programs, and a significant decline in soybean acres have helped reduce Mississippi's losses to soil erosion by nearly 30 percent.
Tillage operations for major field crops have dropped from 10 passes across the field prior to planting in 1977 to fewer than two passes today, says Joe Johnson, North Mississippi Research and Extension Center at Holly Springs.
“Average soil erosion for the state declined from 5.2 tons per acre in 1982 to 3.7 tons in 1997,” he said at the 25th anniversary Southern Conservation Tillage Conference for Sustainable Agriculture, held at Auburn University, citing results from a study done with Herby Bloodworth, USDA Natural Resource Conservation Service, Washington, and Keith McGregor, USDA-Agricultural Research Service National Soil Sedimentation Laboratory, Oxford, Miss..
Though producers in 1977 were averse to giving up their intensive tillage programs, nowadays “conservation tillage is an acceptable practice,” Johnson said.
But, while it has been shown to offer agronomic, economic, and environmental benefits, land operators in the state have been relatively slow to embrace conservation tillage, in comparison to other states, with only about 25 percent of total crop acres planted in conservation tillage during the 1992-1997 period.
The widest acceptance has been with soybeans. From 1992-1997, more than 50 percent of the state's soybeans were planted using conservation tillage, but for corn, “one of the crops easiest to grow with conservation tillage,” acreage was less than 30 percent. For cotton, the total was less than 9 percent.
Over the quarter century from 1997, farm numbers in the state were more than halved, going from 48,000 to only 27,000. The total acres farmed dropped from 15.1 million to about 10 million.
During the period 1982-1997, acreage classified as highly erodible land (HEL) dropped an estimated 655,300 acres, due mainly to a decline in soybeans, which tended to be planted on the more erosive soils, including brown loam areas, which have “some of the most erosive soils in the world,” Johnson said.
Many of the acres taken out of production were entered into the Conservation Reserve Program, he said, helping to reduce sediment in lakes and rivers. Continued implementation of conservation practices and precision farming techniques further reduce nutrient and pesticide runoff.
Conservation practices such as terraces, filter strips, and grassed waterways were helpful in reducing sediment and attached pesticides, thus improving water quality. Although average use of several herbicides ranked among the highest in the nation, research showed filter strips could reduce their loss by as much as 63 percent. One study using tall fescue as filter strips showed herbicide runoff was held to less than 3 percent of the total amount applied.
With the downturn in agricultural commodity prices in the late 1990s and early 2000s, conservation tillage increased rapidly, Johnson said.
While cropland development in the state has been on a downward trend since 1987, “efforts should be made to conserve irrigated cropland and prime farmland. “Research by the Mississippi Agricultural and Forestry Experiment Station, the National Resource Conservation Service Plant Material Center, and the USDA-Agricultural Research Service Soil Sedimentation Laboratory, along with advances in equipment, technology, and herbicides, have proven that conservation tillage is a viable alternative for reducing costs while maintaining crop yields,” Johnson said.
Mississippi is a leader in funds spent for agricultural and forestry research for developing conservation practices.
“We're growing no-till crops successfully and economically, and we're saving soil. Importantly, a lot of farmers' attitudes have changed, too. Conservation tillage has given us something to smile about in Mississippi.”